Methods for the synthesis of tiotropium bromide

ABSTRACT

The present invention relates to methods for synthesizing tiotropium bromide following the scheme: 
                         
Using the above scheme, tiotropium bromide (compound 5A) is obtained under mild conditions and with high yields.

This application is a continuation-in-part of international applicationnumbers PCT/TR2010/000136, filed Jun. 28, 2010; PCT/TR2011/000051, filedFeb. 23, 2011; and PCT/TR2011/000052, filed Feb. 23, 2011, each of whichis incorporated herein by reference in its entirety. This applicationalso claims priority from Turkish patent application numbers 2010/2520,filed Apr. 1, 2010; 2010/05221, filed Jun. 28, 2010; and 2010/05222,filed Jun. 28, 2010.

The present invention relates to a new process for preparing (1α, 2β,4β, 5α,7β)-7-[(Hydroxidi-2-thienylacetyl)oxy]-9,9-dimethyl-3-oxa-9-azoniatricyclo[3.3.1.0^(2,4)]nonane-bromide.

BACKGROUND OF THE INVENTION

The compound whose chemical name is (1α, 2β, 4β, 5α,7β)-7-[(Hydroxidi-2-thienylacetyl)oxy]-9,9-dimethyl-3-oxa-9-azoniatricyclo[3.3.1.0^(2,4)]nonane-bromideis generally known as tiotropium bromide. The compound is shown belowwith formula 5A and was disclosed for the first time in the patentnumbered EP418716.

Tiotropium bromide is a highly effective anticholinergic agent and forthis reason it is widely used for treatment of asthma and/or COPD(chronic obstructive pulmonary disease).

Tiotropium bromide is generally administered to patients via inhalation.For administration via inhalation, dry powder inhalators wherein the drypowder is filled into blisters/capsules or stored in reservoirs can beused. Another method comprises administration of tiotropium bromide withdifferent gases (e.g. HFA134a and/or HFA227) in aerosol form.

Tiotropyum bromide is a very potent agent and therefore even very smallamounts show therapeutic effect.

The patent numbered EP418716 discloses a synthesis method shown inscheme 1 for preparation of tiotropium bromide.

According to this method in the first step scopine that is shown withformula 1A is converted into (2-thienyl)-glycolic acid scopine estershown with formula 7A by reacting with di-(2-thienyl)-glycolic acidmethyl ester that is shown with formula 6A. Afterwards compound offormula 7A is quaternized to give tiotropium bromide.

The first step of this synthesis method is carried out at hightemperatures like 70-90° C. and in presence of dangerous chemicals likesodium methoxide and metallic sodium. The fact that the process iscarried out at high temperatures increases the cost and makes theprocess undesirable for the producers. Furthermore although thereactions are carried out under harsh conditions the yields are in therange of 45% and 70% and all of these reasons show that differentsynthesis methods with higher yields are necessary for preparation oftiotropium bromide.

DETAILED DESCRIPTION OF THE INVENTION

Surprisingly, it was found that, compared to the methods present inprior art, tiotropium bromide was obtained under milder conditions andwith higher yields when the synthesis method according to presentinvention was used. In one aspect, the synthesis method comprises use ofthe method shown in scheme 2.

Upon reaction of scopine or acid addition salts thereof with compound offormula 2A, compound of formula 3A is obtained. Formula 3A is thenconverted to compound of formula 4A by quaternization. Afterwards anoxidation reaction carried out under appropriate conditions convertscompound of formula 4A into the final compound shown with formula 5Awhich is tiotropium bromide.

In another aspect present invention relates to a synthesis method forpreparation of tiotropium bromide (5A) comprising the steps of;

conversion of scopine ester shown with formula 3A,

into quaternized scopine ester shown with formula 4A

and afterwards conversion of formula 4A into the final compoundtiotropium bromide (5A).

Another aspect of the present invention is use of scopine ester shownwith formula 3 in free base form or in form of its acid addition saltsfor synthesis of tiotropium bromide (5A)

In another aspect, another important point of the invention is use ofscopine ester shown with formula 3A in free form or when necessary inthe form of acid addition salts for the preparation of quaternizedscopine ester shown with formula 4A. If scopine ester (3A) is used inthe form of acid addition salts for producing quartenized scopine ester,this salt can be selected from a group comprising hydrochloride,hydrobromide, hydrogenphosphate, hydrogen sulfate, tetrafluoroborate,hexafluorophosphate.

Another aspect of the present invention is related to use of quaternizedscopine ester shown with formula 4 for the synthesis of tiotropiumbromide (5A).

In another aspect, present invention is related to a process forpreparation of tiotropium bromide characterized in that; in the firststep scopine or an acid addition salt thereof,

is reacted with compound of formula 2A

wherein, R group in said compound can be chosen from a group comprisinghydroxy, methoxy, ethoxy, tertiary butoxide, phenoxy, O—N-succinimide,O—N-phatalimide, phenyloxy, nitrophenyloxy, pentafluorophenyloxy,vinyloxy, —S-methyl, —S-ethyl, —S-phenyl, to give scopine ester shownwith formula 3A

and in the second step, compound of formula 3A is quaternized inpresence of methyl bromide to give compound of formula 4A

and in the third step compound of formula 4A is subjected to anoxidation reaction in presence of organic/inorganic basic compounds inoxygen containing atmosphere to give tiotropium bromide.

Compound of formula 2A which can be used to prepare scopine ester offormula 3A is a compound where R is selected from methoxy, ethoxy,tertiary butoxide, phenoxy, O—N-succinimide, O—N-phatalimide, phenyloxy,nitrophenyloxy, fluorophenyloxy, pentafluorophenyloxy, vinyloxy,—S-methyl, —S-ethyl, —S-phenyl and hydroxy.

Due to importance of the use of compound of formula 2A in the synthesisof tiotropium bromide as a starting material, another aspect of thepresent invention relates to use of compound of formula 2A as a startingmaterial for the preparation of tiotropium bromide (5A).

In accordance with the present invention, scopine (1A) can be used infree form or in the form of its acid addition salts such ashydrochloride, hydrobromide, hydrogenphosphate, hydrogensulfate,tetrafluoroborate and hexafluorophosphate. Preferably it is used in freeform.

Accordingly a method for preparation of scopine ester shown with formula3A comprises dissolving scopine in an organic solvent, for example;dimethylformamide (DMF), dimethyl sulfoxide (DMSO), benzene, toluene,diethyl ether, tetrahydrofuran, ethanol, methanol, acetonitrile,acetone, ethyl acetate, methyl ethyl ketone, dichloromethane, dioxane,dimethylacetamide, N-methylpyrrolidone, hexane, heptane or a mixture ofthese solvents, preferably dimethylformamide or dichloromethane is used.

If scopine is used in the form of its acid addition salt then a base isadded to the solution in order to liberate scopine. According to presentinvention the base is selected from a group consisting of organic orinorganic bases, for example; from a group comprising triethylamine,diisopropylethylamine, pyridine, dimethylaminopyridine,N-methylpyrrolidine, N-methylmorpholine or ammonia. Preferably ammoniais used. Said basic compound is used in an amount of at least 1 mole,preferably in an amount of 1.25 to 2.5 moles, more preferably in anamount of 1.5 to 2.0 moles per 1 mole of scopine used. Addition of thebasic compound can take place at a temperature of 0 to 60° C.,preferably 15 to 50° C., and more preferably 20 to 30° C. Afterwards theobtained mixture is stirred for 0.5 to 3 hours, more preferably for 1 to2 hours at a fixed temperature. The salt that forms during the reactionis separated by filtration and the solvent present in the obtainedsolution is distilled under appropriate heat and pressure. Theseconditions are determined according to the nature of the solvent used.

The compound obtained is then dissolved in an appropriate organicsolvent, for example, dimethylformamide (DMF), dimethyl sulfoxide(DMSO), benzene, toluene, diethyl ether, tetrahydrofuran, ethanol,methanol, acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone,hexane, heptane or a mixture thereof and compound of formula 2A is addedto the formed solution.

The compound of formula 2A used in this process is selected fromcompounds wherein R is selected from a group comprising methoxy, ethoxy,tertiary butoxide, phenoxy, O—N-succinimide, O—N-phatalimide, phenyloxy,nitrophenyloxy, fluorophenyloxy, pentafluorophenyloxy, vinyloxy,—S-methyl, —S-ethyl, —S-phenyl and hydroxy.

If the R group in formula 2A is methoxy, ethoxy, vinyloxy, phenyloxy,—S-methyl, —S-ethyl or —S-phenyl then the reaction is carried out inpresence of an organic or inorganic base. As organic base alkalicarbonates, or earth alkali carbonates; lithium carbonate, sodiumcarbonate, potassium carbonate, calcium carbonate, sodium hydride,potassium hydride, calcium hydride, sodium methylate, sodium ethylate,potassium methylate or potassium ethylate can be used. As inorganic baseone of the hydrides mentioned above is used. Preferably sodium hydrideis used. Said basic compound is added at least in stoichiometric amount,preferably in 1 to 3 moles, more preferably 1.5 to 2 moles per mole ofscopine. The solution obtained after addition of the base is stirred for10-120 minutes preferably for 30-90 minutes. If the compound of formula2A is an ester wherein R is methoxy or ethoxy then the reaction iscarried out at a temperature of 40-90° C. preferably at 50-80° C. andmore preferably at 60-75° C., under vacuum in order to distill off thealcohol that forms as a side product and thus shift the reaction to theside of the scopine ester.

After completion of the distillation, if necessary, solvent that wasalso removed during the distillation of the side product can be addedagain. The obtained solution is then cooled to −5 to 40° C., preferablyto 0-35° C., more preferably to 10-25° C. Hydrochloric acid is thenadded to said solution over 12-120 minutes, preferably over 25-50minutes. Hydrochloric acid used in this step can be in gaseous form orin form of an aqueous solution; preferably aqueous solution ofhydrochloric acid is used. Per one mole of scopine, 80-350 ml,preferably 120-225 ml of 36% hydrochloric acid that is dissolved in10-20 liters, preferably 12-17 liters of water is added.

After addition of hydrochloric acid solution is complete, the aqueousphase is separated and washed with a water immiscible organic solvent,for example methylene chloride, ethylacetate, toluene, n-butyl acetate,preferably with dichloromethane and then the organic layer is separatedand discarded. This step can be repeated if necessary.

The aqueous phase that is obtained is combined with a water immiscibleorganic solvent, for example; methylene chloride, ethylacetate, toluene,n-butylacetate and an inorganic base, for example carbonates of alkalimetals or alkali earth metals for example; lithium carbonate, sodiumcarbonate, potassium carbonate, calcium carbonate and preferably sodiumcarbonate is added and pH of the solution is adjusted to 7.5-11,preferably 8-10. Inorganic base is preferably added in the form of itsaqueous solution. Accordingly, per mole of scopine, 50-400 g, preferably100-200 g inorganic base is used by dissolving in 0.25-1.5 L, preferablyin 0.5-1.0 L, most preferably in 0.7-0.8 L of water.

After thoroughly mixing the obtained mixture, organic layer isseparated. Aqueous phase is washed with a water immiscible organicsolvent, for example methylene chloride, ethyl acetate, toluene,n-butylacetate, if necessary this step can be repeated one more time,afterwards organic layers are combined and the organic solvent isremoved under appropriate heat and pressure.

The compound obtained after distillation is dissolved in an appropriatesolvent, for example dimethylformamide (DMF), dimethyl sulfoxide (DMSO),benzene, toluene, diethyl ether, tetrahydrofuran, ethanol, methanol,acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone,hexane, heptane and a mixture thereof and the obtained solution isheated to the boiling point of the solvent and afterwards slowly cooledto a temperature between −10 to 20° C. Scopine ester that is obtained asa result of this solution is separated by filtration and dried undervacuum.

When R group that is in the compound shown with formula 2A is hydroxy,this compound is shown with formula 2aA;

The synthesis method for obtaining scopine ester shown with formula 3Acomprises the steps of; preparing scopine or an acid addition saltthereof as described before and then dissolving said compound in anappropriate solvent, for example; dimethylformamide (DMF), dimethylsulfoxide (DMSO), benzene, toluene, diethylether, tetrahydrofuran,ethanol, methanol, acetonitrile, acetone, ethyl acetate, methyl ethylketone, dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone, hexane, heptane or a mixture thereof and addition ofcompound of formula 2A wherein R group is hydroxy to said solution andafterwards adding N,N-dicyclohexylcarbodiimide (DCC)1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) orN,N′-diisopropylcarbodiimide and optionally 4-dimethylaminopyridine(DMAP). Said reaction mixture is stirred at a temperature of 0-40° C.,preferably at room temperature for 10-48, preferably for 12-18 hours.

In this reaction per one mole of scopine, at least 1 mole, preferably1.05-3 moles, more preferably 1.1-1.8 moles of DCC, EDC or DCI is used.Optionally, per one mole of scopine at least 0.01 moles, preferably 0.03to 0.2 moles, more preferably 0.05-0.1 moles of DMAP can be added.

At the end of the reaction if solid particles form, the solution isfiltered to remove these solid particles, then the solution obtained isdiluted with an appropriate organic solvent, for example;dichloromethane, ethyl acetate, hexane, heptanes, and then extractedwith water. After removal of organic phase from water phase, the solventthat is used is removed under appropriate conditions. At this point theconditions, e.g. the temperature and pressure, are determined accordingto the nature of the solvent that is used.

The obtained compound can be purified with conventional purificationmethods; for example, crystallization with anti-solvent, crystallizationwith active carbon, thin layer chromatography (TLC), columnchromatography, high pressure liquid chromatography (HPLC), distillationetc. if need be.

A method for preparation of quaternized scopine ester shown with formula4A comprises, dissolving scopine ester shown with formula 3A and/or acidaddition salts thereof and a methyl bromide solution comprising methylbromide in an amount 10-90%, preferably 30-60% by weight in a suitableorganic solvent; for example dimethylformamide (DMF), dimethyl sulfoxide(DMSO), benzene, toluene, diethylether, tetrahydrofuran, ethanol,methanol, acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone,hexane, heptane or a mixture thereof and stirring the formed mixture ata temperature of 0-40° C., preferably at room temperature for 12-90hours, preferably for 18-72 hours.

Methyl bromide solution is prepared by condensing methyl bromide gas atlow temperature and then mixing the obtained methyl bromide with anorganic solvent; for example, dimethylformamide (DMF), dimethylsulfoxide (DMSO), benzene, toluene, diethyl ether, tetrahydrofuran,ethanol, methanol, acetonitrile, acetone, ethyl acetate, methyl ethylketone, dichloromethane, dioxane, dimethylacetamide,N-methylpyrrolidone, hexane, heptane or a mixture thereof. The solutionis preferably prepared in acetonitrile.

The compound that is obtained can be purified by one of the conventionalpurification methods for example; crystallization by anti-solvent,crystallization by use of active carbon, thin layer chromatography(TLC), column chromatography, high pressure liquid chromatography(HPLC), distillation etc.

A process for preparation of tiotropium bromide comprises, dissolvingquaternized scopine ester compound shown with formula 4A in an organicsolvent, for example dimethylformamide (DMF), dimethyl sulfoxide (DMSO),benzene, toluene, diethyl ether, tetrahydrofuran, ethanol, methanol,acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone,hexane, heptane or a mixture thereof that is saturated with oxygen.Preferably acetonitrile or dichloromethane that is saturated with oxygenis used. Then an inorganic base for example; potassium carbonate, sodiumcarbonate, potassium hydrogen carbonate, sodium hydrogen carbonate,sodium tert-butoxide, triethylamine is added to the formed solution, theformed mixture is stirred at a temperature of −78 to 70° C., preferablyat −30 to 60° C., for 1-72 hours, preferably for 3-48 hours.

The compound that is obtained can be purified by one of the conventionalpurification methods for example; crystallization by anti-solvent,crystallization by use of active carbon, thin layer chromatography(TLC), column chromatography, high pressure liquid chromatography(HPLC), distillation etc.

The present invention also relates to, new intermediates namely; scopineester shown with formula 3A and its acid addition salts, for examplehydrochloride, hydrobromide, hydrogenphosphate, hydrogen sulphate,tetrafluoroborate, hexafluorophosphate salts

And quaternized scopine ester shown with formula 4A,

And use of these intermediates for preparation of tiotropium bromide.

The present invention also relates to, pharmaceutical compositionscomprising tiotropium bromide prepared according to the presentinvention and use of said pharmaceutical compositions for the treatmentof pulmonary diseases such as asthma, chronic obstructive pulmonarydisease (COPD) and allergic rhinitis.

In one aspect, the synthesis method to obtain tiotropium bromidecomprises the use of the procedure demonstrated in scheme 3.

The final product in formula 4B is obtained with higher efficacy andpurity when the compound demonstrated in formula 3B is transformed intoformula 4B without being isolated.

According to this, one of the constituents of the present invention isthe tiotropium bromide synthesis process in which the compound shown informula 3B that is obtained as a result of the reaction of formula 1Band formula 2B is transformed into formula 4B under convenientconditions without being isolated.

The present invention has decreased the cost of the manufacture byeliminating a purification process that is supposed to be used in theprocess and managed to obtain formula 4B with higher efficacy.

In one aspect, the present invention relates to a process so as to beused in the synthesis of tiotropium bromide and it comprises the stepsof;

-   -   a) Obtaining the compound given in formula 3B as a result of the        reaction of scopine which is demonstrated in formula 1B or acid        addition salts thereof with the compound demonstrated in formula        2B,    -   b) Transforming the substance, which is obtained after the solid        matter in the reaction mixture is removed through filtration,        into formula 4B without being subjected to any purification        processes,    -   c) Transforming the quaternized scopine ester demonstrated in        formula 4B into tiotropium bromide under convenient oxidation        conditions.

According to another aspect, the present invention relates to a methodfor preparation of tiotropium bromide and comprises the steps thatscopine (1B) or an acid addition salt thereof

and the compound demonstrated in formula 2B,

wherein the group R in said compound can be selected from a groupcomprising hydroxy, methoxy, ethoxy, tertiary butoxide, phenoxy,O—N-succinimide, O—N-phthalimide, phenyloxy, nitrophenyloxy,fluorophenyloxy, pentafluorophenyloxy, vinyloxy, —S-methly, —S-ethyl and—S-phenyl, react

and scopine ester demonstrated in formula 3B is obtained at the end ofthe reaction; the compound illustrated in formula 4B is obtained byquaternizing the substance shown in formula 3B with methyl bromide atthe second stage; formula 4B

is subjected to oxidation reaction in oxygenic environment by usingorganic and/or inorganic basic substances and the final producttiotropium bromide is obtained at the third stage.

According to the present invention, scopine (1B) can be in free form orin the form of an acid addition salt thereof, for instancehydrochloride, hydrobromide, hydrogenphosphate, hydrogensulphate,tetrafluoroborate and hexafluorophosphate salts. Preferably, it is usedin free form.

According to this, the method for the preparation of scopine esterdemonstrated in formula 3B requires scopine to dissolve in anappropriate organic solvent, for instance in dimethylformamide (DMF),dimethyl sulfoxide (DMSO), benzene, toluene, diethyl ether,tetrahydrofurane, ethanol, methanol, acetonitrile, acetone, ethylacetate, methyl ethyl ketone, dichloromethane, dioxane,dimethylacetamide, N-methylpyrrolidone, hexane, heptane or a combinationthereof. Preferably, dimethylformamide or dichloromethane is used.

If scopine is used in the form of its acid addition salt, a base isadded in order to reveal scopine. According to the present invention,said base can be selected from a group comprising organic and inorganicbases, for instance from the organic amines triethylamine,diisoprophylethylamine, pyridine, dimethylaminopyridine,N-methylprolidine, N-methyl morphorline or ammoniac. Preferably,ammoniac is used. The amount of said basic substance added is in therange of 1.25-2.5 moles per mole of scopine salt used, preferably in therange of 1.5-2.0 moles per mole of scopine salt used. The basicsubstance can be added at 0-60° C., preferably at 15-50° C., mostpreferably at 20-30° C. Following this, the mixture obtained is stirredat constant temperature for 0, 5-3 hours, preferably for 1-2 hours. Thesalt which is produced during the reaction is filtered and removed. Thesolvent in the obtained solution is distilled under convenienttemperature and pressure conditions. These conditions are determinedbased on the type of the solvent used.

Following this, the substance obtained is dissolved in an appropriateorganic solvent, for instance in dimethylformamide (DMF), dimethylsulfoxide (DMSO), benzene, toluene, diethyl ether, tetrahydrofurane,ethanol, methanol, acetonitrile, acetone, ethyl acetate, methyl ethylketone, dichloromethane, dioxane, dimethylacetamide,N-methylpyrrolidone, hexane, heptane or a combination thereof, and thenformula 2B is added.

According to the present invention, the compound of formula 2B to beused here is chosen from a group of compounds wherein R is composed ofhydroxy, methoxy, ethoxy, tertiary, butoxide, phenoxy, O—N— succinimide,O—N-phthalimide, phenyloxy, nitrophenyloxy, fluorophenyloxy, vinyloxy,—S-methly, —S-ethyl and hydroxyl.

In the case that R is methoxy, ethoxy, phenyloxy, —S-methly, —S-ethyl or—S-phenyl as formula 2B, the reaction is realized in the presence of abase.

The organic base can be selected from a group comprising alkalicarbonates or alkaline earth carbonates, lithium carbonate, sodiumcarbonate, potassium carbonate, calcium carbonate, sodium hydride,potassium hydride, calcium hydride, sodium methylate, sodium ethylate,potassium methylate and potassium ethylate. As the inorganic base, oneof the hydrides is used. Most preferably, sodium hydride is used. Theamount of said base used is at least at the stoichiometric proportion,preferably 1-3 moles, most preferably 1, 5-2 moles per mole of scopine.The solution which is obtained after the base is added is stirred for10-120 minutes, preferably for 30-90 minutes. If the formula 2B used isan ester wherein the R it includes is methoxy or ethoxy, the reaction isrealized at 40-90° C., preferably at 50-80° C., most preferably at60-75° C. and preferably under vacuum, and it is provided that thealcohol which is produced as a byproduct during the reaction isdistilled and separated. Therefore, the balance of the reaction isreadjusted towards scopine ester.

After the distillation is complete, the distilled solvent content of thereaction solution can be added again when necessary. The solutionobtained is cooled to 5-40° C., preferably to 0-35° C., most preferablyto 10-25° C. after the distillation is finished. The solution at thistemperature is added hydrochloric acid for 12-120 minutes, preferablyfor 25-50 minutes. The hydrochloric acid used here can be in gas oraqueous solution form. However, it is preferred to be in aqueoussolution form. Per one mole of scopine used, 80-350 ml of 36%hydrochloric acid, particularly 120-225 ml of 36% hydrochloric acid isadded as dissolved in 10-20 liters of water, preferably in 12-17 litersof water.

Subsequent to the addition of hydrochloric acid solution, aqueous phaseis separated. It is washed with a water immiscible organic solvent suchas methylene chloride, ethyl acetate, toluene, n-butyl acetate, butpreferably methylene chloride; organic phase is separated and removed.This step can be repeated if required.

The obtained aqueous phase is mixed with a water immiscible organicsolvent such as methylene chloride, ethyl acetate, toluene, n-butylacetate, and the pH value of the solution is adjusted in the range of 7,5-11, preferably in the range of 8-10 by adding an inorganic base intoit, for instance carbonates of alkali metals or alkaline earth metalssuch as lithium carbonate, sodium carbonate, potassium carbonate,calcium carbonate, most preferably sodium carbonate. The inorganic baseis preferably added in the form of aqueous phase. According to this,50-400 g, preferably 100-200 g of organic base per one mole is used asdissolved in 0.5-1.0 L, particularly preferably in 0.7-0.8 L of water.

After the obtained mixture is stirred, the organic phase is separated.The aqueous phase is extracted with a water immiscible organic solventsuch as methylene chloride, ethyl acetate, toluene, n-butyl acetate.This step can be repeated if required. Then, the organic phases arecombined and the organic solvent is distilled at an appropriatetemperature and pressure to be removed.

The substance obtained upon distillation is dissolved in an appropriatesolvent, for instance in a solvent combination which is comprised ofdimethylformamide (DMF), dimethyl sulfoxide (DMSO), benzene, toluene,diethyl ether, tetrahydrofurane, ethanol, methanol, acetonitrile,acetone, ethyl acetate, methyl ethyl ketone, dichloromethane, dioxane,dimethylacetamide, N-methylpyrrolidone, hexane, heptane or a combinationthereof. The obtained solution is heated up to the boiling point of thesolvent used, and then it is slowly cooled to −10-20° C. Scopine esterwhich is obtained upon this procedure is filtered from the solution anddried under vacuum.

In the case that the group R in the compound, which is demonstrated informula 2B, is hydroxy (formula 2aB),

the synthesis method that will be used so as to obtain scopine esterillustrated in formula 3B comprises the steps of preparing scopine andacid addition salt thereof as described above; dissolving it in anappropriate solvent such as dimethylformamide (DMF), dimethyl sulfoxide(DMSO), benzene, toluene, diethyl ether, tetrahydrofurane, ethanol,methanol, acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone,hexane, heptane or a combination thereof; adding the compound whereinthe group R is hydroxyl which is demonstrated in formula 2B into theobtained solution; and adding N,N′-dicyclohexylcarbodiimide (DCC),1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) orN,N′-diisopropylcarbodiimide (DIC) and optionally4-dimethylaminopyridine (DMAP) into the obtained solvent. Said reactionis stirred at −10-40° C., preferably at room temperature for 10-48hours, preferably for 12-16 hours.

In the said reaction, at least 1 mole, preferably 1.05-3 moles, mostpreferably 1.1-1.8 moles DCC, EDC or DIC is added per mole of scopine.Optionally, at least 0.01 mole, preferably 0.03-0.2 mole, mostpreferably 0.05-0.1 mole of DMAP per mole of scopine can be added.

In the case that solid particles remain in the solution at the end ofthe reaction, the solution is put through filtration. The solution thatis obtained after the solid substance is filtered is diluted with anorganic solvent, for instance dichloromethane, ethyl acetate, hexane,heptane, and it is extracted with water. After the organic phase isseparated from the aqueous phase, the solvent used is removed underconvenient conditions. The conditions to be used here, such astemperature and pressure, are chosen in accordance with the type of thesolvent used.

Without being subjected to any purification operations, the obtainedsubstance is dissolved in an appropriate organic solvent, for instancein a solvent combination which is comprised of dimethylformamide (DMF),dimethyl sulfoxide (DMSO), benzene, toluene, diethyl ether,tetrahydrofurane, ethanol, methanol, acetonitrile, acetone, ethylacetate, methyl ethyl ketone, dichloromethane, dioxane,dimethylacetamide, N-methylpyrrolidone, hexane, heptane or a combinationthereof and the organic solution which contains 90-10%, preferably30-60% of methyl bromide by weight is added into it. Then, it is stirredat 0-40° C., preferably at room temperature for 12-90 hours, preferablyfor 18-72 hours and the quaternized scopine ester that is demonstratedin formula 4B is obtained.

According to another aspect, the present invention comprises thetransformation of scopine ester which is demonstrated in formula 3B intoquaternized scopine ester which is demonstrated in formula 4B withoutbeing subjected to any chromatographic purification processes.

The methyl bromide solution mentioned here is obtained throughcondensing methyl bromide gas at low temperature, then dissolving it ina desired organic solvent, for instance in a solvent combination whichis comprised of dimethylformamide (DMF), dimethyl sulfoxide (DMSO),benzene, toluene, diethyl ether, tetrahydrofurane, ethanol, methanol,acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone,hexane, heptane or a combination thereof. Preferably, it is dissolved inacetonitrile solution.

If required, the obtained substance can be purified through one of theconventional purification methods such as anti-solvent crystallization,activated charcoal crystallization, thin layer chromatography (TLC),column chromatography, high pressure liquid chromatography (HPLC),distillation and the methods in the prior art.

The method for the preparation of tiotropium bromide which isillustrated in formula 5B is comprised of the stages of dissolvingquaternized scopine ester demonstrated in formula 4B in anoxygen-saturated organic solvent, for example in a solvent that iscomprised of dimethylformamide (DMF), dimethyl sulfoxide (DMSO),benzene, toluene, diethyl ether, tetrahydrofurane, ethanol, methanol,acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone,hexane, heptane or a combination thereof, preferably in acetonitrile ordichloromethane; adding an organic or an inorganic base such aspotassium carbonate, sodium carbonate, potassium hydrogen carbonate,sodium tert-butoxide, triethyl amine into the obtained solvent; andstirring the obtained blend at −78-70° C., preferably at −30-60° C. for1-72 hours, preferably for 3-48 hours.

Another constituent of the present invention is that tiotropium bromidewhich is prepared according to the present invention is used in theproduction of a drug so as to be used in the treatment of manyrespiratory diseases, especially in asthma, chronic obstructive lungdisease (COPD) and allergic rhinitis.

An alternative method for the synthesis of tiotropium bromide (formula6C)

comprises that; di-(2-thienyl)-acetic acid shown in formula 1C

is transformed into formula 2C which is a form of acid anhydride;

scopine ester that is demonstrated in formula 4C is obtained throughreacting the obtained acid anhydride with scopine;

the compound shown in formula 5C is obtained upon quaternizing scopineester with methyl bromide;

the compound obtained at the end is transformed into tiotropium bromideafter it is processed with organic and/or inorganic basic substances.

Steiglich esterification, which is a commonly utilized method tosynthesize esters by using alcohol and carboxylic acid, comprises theuse of a chemical called N,N′-dicyclohexylcarbodiimide (DCC). However,there appears some problems in the purification of the final productobtained since dicyclohexylurea is produced at the end of the reactionas a byproduct of this chemical.

According to this, a method so as to be used in the synthesis of scopineester shown in formula 4C which is a significant intermediate productfor the synthesis of tiotropium bromide

comprises the steps of obtaining di-(2-thienyl)-acetic acid anhydridedemonstrated in formula 2C through the reaction of di-(2-thienyl)-aceticacid (1) with DCC;

then obtaining scopine ester shown in formula 4C through the reaction ofthe compound demonstrated in formula 2C and scopine with4-dimethylaminopyridine (DMAP).

The inventors have found that dicyclohexylurea, which is the byproductof DCC, is eliminated at the previous stage of the synthesis, andtherefore purer scopine ester (4C) is obtained.

According to this, the method for the synthesis of di-(2-thienyl)-aceticacid anhydride shown in formula 2C comprises the steps of dissolvingdi-(2-thienyl)-acetic acid in an appropriate organic solvent such asdimethylformamide (DMF), dimethyl sulfoxide (DMSO), benzene, toluene,diethyl ether, tetrahydrofurane, ethanol, methanol, acetonitrile,acetone, ethyl acetate, methyl ethyl ketone, dichloromethane, dioxane,dimethylacetamide, N-methyl pyrrolidone, hexane, heptane or acombination thereof, most preferably in dichloromethane ordimethylformamide; then adding dicyclohexylcarbodiimide (DCC) into theobtained solution; and stirring it at 0-40° C., preferably at roomtemperature for 10-48 hours preferably for 12-18 hours.

In said reaction, the amount of DCC added per mole ofdi-(2-thienyl)-acetic acid used is at least 0.5 mole, preferably in therange of 0, 55-3 moles, most preferably in the range of 0.6-1.5 moles.

The solid precipitate which comes out at the end of the reaction isseparated through filtration and the solvent in the solution, which isobtained after the solid substance is separated, is removed underconvenient conditions. The conditions to be used here, such astemperature and pressure, are determined according to the type of thesolvent used.

Another constituent of the invention is to develop a new synthesismethod for the preparation of scopine ester shown in formula 4C.

According to this, the method for the preparation of scopine ester shownin formula 4C comprises the steps of dissolving scopine anddi-(2-thienyl)-acetic acid anhydride in an appropriate organic solventsuch as dimethylformamide (DMF), dimethyl sulfoxide (DMSO), benzene,toluene, diethyl ether, tetrahydrofurane, ethanol, methanol,acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone,hexane, heptane or a combination thereof, most preferably indichloromethane or dimethylformamide; then adding DMAP into the obtainedsolution; and stirring it at 0-40° C., preferably at room temperaturefor 10-48 hours preferably for 12-18 hours.

In said reaction, the amount of di-(2-thienyl)-acetic acid anhydrideused per mole of scopine used is at least 1 mole, preferably in therange of 1.05-4 moles, most preferably in the range of 1.1-3.0 moles.

In said reaction, the amount of DMAP added per mole of scopine used isat least 0.05 mole, preferably in the range of 0.1-2.0 moles, mostpreferably in the range of 0.3-1.0 mole.

After the reaction, the amount of distilled water added into the mixtureper mole of di-(2-thienyl)-acetic acid anhydride is at least 0.01 mole,preferably in the range of 0.02-0.2 mole, most preferably in the rangeof 0.05-0.1 mole. After the distilled water is added, the mixture isstirred at room temperature for 2 hours.

The obtained reaction mixture is diluted by an appropriate organicsolvent, for example by DMF, DMSO, benzene, toluene, diethyl ether,tetrahydrofurane, ethanol, methanol, acetonitrile, acetone, ethylacetate, methyl ethyl ketone, dichloromethane, dioxane,dimethylacetamide, N-methyl pyrrolidone, hexane, heptane or acombination thereof, most preferably by dichloromethane ordimethylformamide; and it is extracted with aqueous solutions 1M NaHSO₄,10% Na₂CO₃ and saturated NaCl respectively. The accumulated solventlayer is dried with and anhydrous Na₂SO₄ filtered. The organic solventin the solution obtained is removed under convenient temperature andpressure. The conditions to be used here are determined according to thetype of the solvent used.

If required, the obtained substance can be purified through one of theconventional purification methods such as anti-solvent crystallization,activated charcoal crystallization, thin layer chromatography (TLC),column chromatography, high pressure liquid chromatography (HPLC),distillation and the methods in the prior art.

The method for the preparation of quaternized scopine ester which isillustrated in formula 5C is comprised of the stages of dissolvingscopine ester demonstrated in formula 4C and the organic solution whichcontains 10-90%, preferably 30-60% methylbromide in an appropriatesolvent, for example in a solvent that is comprised of dimethylformamide(DMF), dimethyl sulfoxide (DMSO), benzene, toluene, diethyl ether,tetrahydrofurane, ethanol, methanol, acetonitrile, acetone, ethylacetate, methyl ethyl ketone, dichloromethane, dioxane,dimethylacetamide, N-methylpyrrolidone, hexane, heptane or a combinationthereof, and stirring the obtained mixture at 0-40° C., preferably atroom temperature for 12-90 hours, preferably for 18-72 hours.

The methyl bromide solution mentioned here is obtained throughcondensing methyl bromide gas at low temperature, then dissolving it ina desired organic solvent, for instance in a solvent combination whichis comprised of dimethylformamide (DMF), dimethyl sulfoxide (DMSO),benzene, toluene, diethyl ether, tetrahydrofurane, ethanol, methanol,acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone,hexane, heptane or a combination thereof. Preferably, it is dissolved inacetonitrile solution.

If required, the obtained substance can be purified through one of theconventional purification methods such as anti-solvent crystallization,activated charcoal crystallization, thin layer chromatography (TLC),column chromatography, high pressure liquid chromatography (HPLC),distillation and the methods in the prior art.

The method for the preparation of tiotropium bromide which isillustrated in formula 6C is comprised of the stages of dissolvingquaternized scopine ester demonstrated in formula 5C in anoxygen-saturated organic solvent, for example in a solvent that iscomprised of dimethylformamide (DMF), dimethyl sulfoxide (DMSO),benzene, toluene, diethyl ether, tetrahydrofurane, ethanol, methanol,acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methylpyrrolidone,hexane, heptane or a combination thereof, preferably in acetonitrile ordichloromethane; adding an organic or an inorganic base such aspotassium carbonate, sodium carbonate, potassium hydrogen carbonate,sodium tert-butoxide, triethyl amine into the obtained solvent; andstirring the obtained mixture at −78-70° C., preferably at −30-60° C.for 1-72 hours, preferably for 3-48 hours.

If required, the obtained substance can be purified through one of theconventional purification methods such as anti-solvent crystallization,activated charcoal crystallization, thin layer chromatography (TLC),column chromatography, high pressure liquid chromatography (HPLC),distillation and the methods in the prior art.

According to another aspect, the present invention comprisesdi-(2-thienyl)-acetic acid anhydride shown in formula 2C

and the use of this substance in the synthesis of tiotropium bromide.

EXAMPLES

The examples below are given to explain the subject-matter synthesismethod, and the present invention should not be limited with theseexamples.

Example 1 A Process for Preparation of Scopine Ester (3A)

Scopine (155.2 g, 1 mole) and di-(2-thienyl)acetic acid (246.4 g, 1.1moles) are dissolved in dichlorometane (700 ml). DCC (268.2 g, 1.3moles) and DMAP (49 g, 0.4 moles) are then added to the obtainedsolution and the mixture is then stirred at room temperature for 16hours. The solid by-product is filtered off and the obtained clearsolution is concentrated under low pressure. The crude product is thenpurified by column chromatography to give 274.4 g of scopine ester (3)(76% yield).

Example 2 A Process for Preparation of Scopine Ester (3A)

Scopine (7.8 g, 0.05 moles) and di-(2-thienyl)acetic acid (12.3 g, 0.055moles) are dissolved in dichloromethane (80 ml). DCC (15.5 g, 0.075moles) is then added to the obtained solution and the mixture is stirredat room temperature for 16 hours. The solid by-product is filtered off.The solution is then diluted with dichloromethane (20 ml) and extractedwith distilled water (50 ml×3). The organic layer is separated and driedwith anhydrous Na₂SO₄ and filtered. The obtained clear solution isconcentrated under low pressure. The crude product is then purified bycolumn chromatography to give 14.4 g of scopine ester (3A) (80% yield)

Example 3 A Process for Preparation of Scopine Ester (3A)

Scopine (11.6 g, 0.075 moles) and di-(2-thienyl)acetic acid (20.2 g,0.09 moles) are dissolved in dimethylformamide (50 ml). EDC (14.0 g,0.09 moles) is then added to the obtained solution and the mixture isstirred for 16 hours at room temperature. The organic solvent is thenremoved under reduced pressure at a temperature of 50° C. The obtainedproduct is then diluted with dichloromethane (100 ml) and extracted withdistilled water (100 ml×3). The organic phase obtained at the end of theextraction process is separated and then dried with anhydrous Na₂SO₄ andfiltered. The organic solvent is then removed under reduced pressure togive 19.5 g of scopine ester (3A) (72% yield).

Example 4 A Process for Preparation of Scopine Ester (3A)

Scopine (15.5 g, 0.1 moles) and di-(2-thienyl)acetic acid (24.6 g, 0.11moles) are dissolved in dichloromethane (100 ml). EDC (17.1 g, 0.11moles) and DMAP (1.2 g, 0.01 moles) are then added to the obtainedsolution and the mixture is stirred at room temperature for 16 hours.The obtained product is extracted with distilled water (50 ml×3). At theend of extraction process organic phase is separated and dried withanhydrous Na₂SO₄ and then filtered. Organic solvent is then removedunder reduced pressure to give 30.0 g of scopine ester (3A) (83% yield).

Example 5 A Process for Preparation of Scopine Ester (3A)

Scopine (1.4 g, 0.009 moles) and di-(2-thienyl)acetic acid (2.2 g, 0.010moles) are dissolved in dichloromethane (20 ml). DCC (2.04 g, 0.010moles) is then added to the obtained solution and the mixture is stirredat room temperature for 16 hours. The solid by-product is removed byfiltration. The organic solvent is removed under reduced pressure. Thecrude product is then purified by column chromatography to give 1.95 gof scopine ester (3A) (60% yield).

Example 6 A Process for Preparation of Quaternized Scopine Ester (4A)

Scopine ester (3A) (0.8 g, 0.0022 moles) and acetonitrile solution ofmethyl bromide (50% wt/wt) (1 ml) are dissolved in acetonitrile and themixture is the stirred at room temperature for 72 hours. The solidprecipitate is then filtered, washed with a suitable solvent and driedunder low pressure to give 941 mg of quaternized scopine ester (4A) (94%yield).

Example 7 Process for Preparation of Quaternized Scopine Ester (4A)

Scopine ester (3) (0.8 g, 0.0022 moles) and acetonitrile solution ofmethyl bromide (50% wt/wt) (1 ml) is dissolved in acetonitrile (1 ml)and the obtained mixture is stirred at room temperature for 24 hours.The formed solid precipitate is then filtered and washed with a suitablesolvent, e.g. acetonitrile and dried under vacuum to give 981 mg ofquaternized scopine ester (4A) (98% yield).

Example 8 Process for Preparation of Tiotropium Bromide (5A)

Quaternized scopine ester (4A) (0.6 g, 1.32 mmol) and triethylamine(0.36 mL) are dissolved in acetonitrile (12 mL) that is saturated withoxygen gas. The obtained mixture is then stirred at room temperature for48 hours. The precipitate that forms is then filtrated and the solid iswashed with a suitable solvent e.g. acetonitrile, and dried under vacuumto give 460 mg of tiotropium bromide (74% yield).

Example 9 Process for the Preparation of Quaternized Scopine Ester (4B)

Scopine and di-(2-thienyl)acetic acid are dissolved in dichloromethane.The obtained solution is added DCC and the mixture is stirred at roomtemperature for 16 hours. The solid substance in the reaction mixture isremoved through filtration. The solvent in the obtained solution isremoved under low pressure. The raw material obtained is dissolved inacetonitrile and added methyl bromide solution (50% MeBr, inacetonitrile). The tube containing the reaction mixture is closed andthe obtained mixture is stirred at room temperature for 72 hours. Thesolid precipitate which comes out at the end is filtered, washed with asolvent, dried under low pressure and quartenized scopine ester (4B) isobtained (80% efficacy).

Example 10 Process for the Preparation of Quaternized Scopine Ester (4B)

Scopine and di-(2-thienyl)acetic acid are dissolved in dichloromethaneand cooled to −10° C. The solution prepared by dissolving DDC indichloromethane is added to this mixture via a syringe, and then thereaction mixture is stirred at room temperature for 12 hours. The solidsubstance in the reaction mixture is removed through filtration and thesolvent is removed under low pressure. The raw material obtained isdissolved in acetonitrile and added methyl bromide solution (50% MeBr,in acetonitrile). The tube containing the reaction mixture is closed andthe obtained mixture is stirred at room temperature for 72 hours. Thesolid precipitate which comes out at the end is filtered, washed with asolvent, dried under low pressure and quartenized scopine ester (4B) isobtained (76% efficacy).

Example 11 Process for the Preparation of Tiotropium Bromide (5B)

Quaternized scopine ester (4B) and an organic base are dissolved inoxygene-saturated acetonitrile and the obtained mixture is stirred atroom temperature for 48 hours. The solid precipitate which comes out atthe end is filtered, washed with an appropriate solvent such asacetonitrile, dried under low pressure and tiotropium bromide (5B) isobtained (74% efficacy).

Example 12 Process for the Preparation of Di-(2-Thienyl)-Acetic AcidAnhydride (2C)

Di-(2-thienyl)-acetic acid (1C) is dissolved in anhydrous CH₂Cl₂; theobtained mixture is added DCC and stirred for 24 hours at roomtemperature. The solid precipitate which comes out at the end isfiltered and separated. The solvent in the obtained solution is removedat room temperature and under low pressure, and di-(2-thienyl)-aceticacid anhydride (2C) is obtained (78% efficacy).

Example 13 Process for the Preparation of Scopine Ester (4C)

Di-(2-thienyl)-acetic acid anhydride (2C) and scopine are dissolved inanhydrous CH₂Cl₂; the obtained mixture is added DMAP and stirred for 24hours at room temperature. Distilled water is added into the reactionmixture and it is stirred for 2 hours at room temperature. The obtainedmixture is first diluted with CH₂Cl₂, then extracted with aqueoussolutions 1M NaHSO₄, 10% Na₂CO₃ and saturated NaCl respectively. Theorganic part is separated and dried with anhydrous Na₂SO₄. CH₂Cl₂ in thesolution obtained is removed under low pressure at room temperature. Theobtained substance is purified through column chromatography and scopineester (4C) is obtained (84% efficacy).

Example 14 Process for the Preparation of Quaternized Scopine Ester (5C)

Scopine ester (4C) and acetonitrile solution which comprises 50% ofmethyl bromide are dissolved in acetonitrile, and the obtained mixtureis stirred for 72 hours at room temperature. The solid precipitate whichcomes out at the end is filtered, washed with an appropriate solvent,dried under low pressure and quartenized scopine ester (5C) is obtained(94% efficacy).

Example 15 Process for the Preparation of Tiotropium Bromide (6C)

Quaternized scopine ester (5C) and an organic base are dissolved inoxygen-saturated acetonitrile and the obtained mixture is stirred atroom temperature for 48 hours. The solid precipitate which comes out atthe end is filtered, washed with an appropriate solvent such asacetonitrile, dried under low pressure and tiotropium bromide (6C) isobtained (74% efficacy).

The invention claimed is:
 1. A synthesis method for preparation oftiotropium bromide, said method comprising: a) reacting compound 1A or asalt thereof

with compound 2A, wherein R is selected from the group consisting ofhydroxy, methoxy, ethoxy, tertiary butoxide, phenoxy, O—N-succinimide,O—N-phatalimide, phenyloxy, nitrophenyloxy, pentafluorophenyloxy,vinyloxy, and —S-methyl, —S-ethyl, —S-phenyl,

to produce compound 3A,

b) quaternizing compound 3A under conditions that do not require apurification procedure to produce compound 4A, and

c) oxidizing compound 4A to produce compound 5A,

 (tiotropium bromide).
 2. The method according to claim 1, wherein stepa) comprises the steps of dissolving compound 1A and compound 2A,wherein R is hydroxy, in a suitable organic solvent to form a solutionand adding N,N′-dicyclohexylcarbodiimide, 1ethyl-3-(3-dimethylaminopropyl)carbodiimide, orN,N′-diisopropylcarbodiimide to the formed solution.
 3. The methodaccording to claim 1, wherein step b) comprises the step of dissolvingcompound 3A or a salt thereof and 10-90% methyl bromide solution in asuitable organic solvent.
 4. The method according to claim 1, whereinstep c) comprises the steps of dissolving compound 4A in an organicsolvent saturated with oxygen to form a solution and adding an organicor inorganic base to the solution.
 5. The method according to claim 2,wherein N,N′-dicyclohexylcarbodiimide or1-ethyl-3-(3-dimethylaminopropyl)carbodiimide is added.
 6. The methodaccording to claim 2, wherein 4-dimethylaminopyridine is optionallyadded.
 7. The method according to claim 2, wherein the organic solventis selected from the group consisting of dimethylformamide (DMF),dimethyl sulfoxide (DMSO), benzene, toluene, diethylether,tetrahydrofuran, ethanol, methanol, acetonitrile, acetone, ethylacetate, methyl ethyl ketone, dichloromethane, dioxane,dimethylacetamide, N-methyl pyrrolidone, hexane, and heptanes, ormixtures thereof.
 8. The method according to claim 3, wherein 30-60%methyl bromide solution is dissolved in a suitable organic solvent. 9.The method according to claim 3, wherein the organic solvent is selectedfrom the group consisting of dimethylformamide (DMF), dimethyl sulfoxide(DMSO), benzene, toluene, diethylether, tetrahydrofuran, ethanol,methanol, acetonitrile, acetone, ethyl acetate, methyl ethyl ketone,dichloromethane, dioxane, dimethylacetamide, N-methyl pyrrolidone,hexane, and heptanes, or mixtures thereof.
 10. The method according toclaim 4, wherein the organic solvent is acetonitrile or dicloromethane.11. The method according to claim 4, wherein the inorganic base isselected from the group consisting of potassium carbonate, sodiumcarbonate, potassium hydrogen carbonate, sodium hydrogen carbonate,sodium tert-butoxide, and triethylamine.